* [PATCH 1/3] rust: pin-init: internal: pin_init: emit `slot` using mixed site hygiene
2026-09-16 12:11 [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
@ 2026-09-16 12:11 ` Gary Guo
2026-09-16 12:11 ` [PATCH 2/3] rust: pin-init: internal: pin_init: use `slot` identifier directly with mixed site Gary Guo
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Gary Guo @ 2026-09-16 12:11 UTC (permalink / raw)
To: Benno Lossin, Gary Guo, Miguel Ojeda, Boqun Feng,
Björn Roy Baron, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan
Cc: rust-for-linux, linux-kernel
Syn/quote's default is the call site hygiene. If user provides a field
named `slot`, it will conflict with pin-init generated `slot` identifier.
Change it to use mixed site hygiene instead.
Fixes: 4883830e9784 ("rust: pin-init: rewrite the initializer macros using `syn`")
Signed-off-by: Gary Guo <gary@garyguo.net>
---
rust/pin-init/internal/src/init.rs | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs
index dc5dfb2ca114..6ade192d27e6 100644
--- a/rust/pin-init/internal/src/init.rs
+++ b/rust/pin-init/internal/src/init.rs
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: Apache-2.0 OR MIT
use proc_macro2::{Span, TokenStream};
-use quote::{format_ident, quote, ToTokens, TokenStreamExt};
+use quote::{format_ident, quote, quote_spanned, ToTokens, TokenStreamExt};
use syn::{
braced, parenthesized,
parse::{End, Parse},
@@ -269,7 +269,7 @@ fn expand(
},
|(_, err)| Box::new(err),
);
- let slot = format_ident!("slot");
+ let slot = Ident::new("slot", Span::mixed_site());
let (has_data_trait, get_data, init_from_closure) = if pinned {
(
format_ident!("HasPinData"),
@@ -302,7 +302,7 @@ fn assert_zeroable<T: ?::core::marker::Sized>(_: *mut T)
};
let this = match this {
None => quote!(),
- Some(This { ident, .. }) => quote! {
+ Some(This { ident, .. }) => quote_spanned! { Span::mixed_site() =>
// Create the `this` so it can be referenced by the user inside of the
// expressions creating the individual fields.
let #ident = unsafe { ::core::ptr::NonNull::new_unchecked(slot) };
@@ -312,7 +312,7 @@ fn assert_zeroable<T: ?::core::marker::Sized>(_: *mut T)
let data = Ident::new("__data", Span::mixed_site());
let init_fields = init_fields(&fields, pinned, &data, &slot);
let field_check = make_field_check(&fields, init_kind, &path);
- Ok(quote! {{
+ Ok(quote_spanned! { Span::mixed_site() => {
// Get the data about fields from the supplied type.
// SAFETY: TODO
let #data = unsafe {
@@ -512,7 +512,7 @@ fn make_field_check(
..::core::mem::zeroed()
}),
};
- quote! {
+ quote_spanned! { Span::mixed_site() =>
#[allow(unreachable_code)]
// We use unreachable code to perform field checks. They're still checked by the compiler.
// SAFETY: this code is never executed.
--
2.54.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/3] rust: pin-init: internal: pin_init: use `slot` identifier directly with mixed site
2026-09-16 12:11 [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
2026-09-16 12:11 ` [PATCH 1/3] rust: pin-init: internal: pin_init: emit `slot` using mixed site hygiene Gary Guo
@ 2026-09-16 12:11 ` Gary Guo
2026-09-16 12:11 ` [PATCH 3/3] rust: pin-init: internal: pin_init: provide span for slot projection Gary Guo
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Gary Guo @ 2026-09-16 12:11 UTC (permalink / raw)
To: Benno Lossin, Gary Guo, Miguel Ojeda, Boqun Feng,
Björn Roy Baron, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan
Cc: rust-for-linux, linux-kernel
Use `quote_spanned!(Span::mixed_site() => ...)` directly instead of
creating `slot` identifier and interpolate it later. Do the same for
`__data`, too.
This is needed so that we can customize the location of the span without
having the `slot` identifier getting in the way. For example:
quote_spanned!(Span::mixed_site().located_at(loc) => ...)
with `slot` mentioned directly will have the diagnostic pointing to the
desired location, while `#slot` won't.
Signed-off-by: Gary Guo <gary@garyguo.net>
---
rust/pin-init/internal/src/init.rs | 31 ++++++++++++-------------------
1 file changed, 12 insertions(+), 19 deletions(-)
diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs
index 6ade192d27e6..a77ffef9926b 100644
--- a/rust/pin-init/internal/src/init.rs
+++ b/rust/pin-init/internal/src/init.rs
@@ -269,7 +269,6 @@ fn expand(
},
|(_, err)| Box::new(err),
);
- let slot = Ident::new("slot", Span::mixed_site());
let (has_data_trait, get_data, init_from_closure) = if pinned {
(
format_ident!("HasPinData"),
@@ -286,7 +285,7 @@ fn expand(
let init_kind = get_init_kind(rest, dcx);
let zeroable_check = match init_kind {
InitKind::Normal => quote!(),
- InitKind::Zeroing => quote! {
+ InitKind::Zeroing => quote_spanned! { Span::mixed_site() =>
// The user specified `..Zeroable::zeroed()` at the end of the list of fields.
// Therefore we check if the struct implements `Zeroable` and then zero the memory.
// This allows us to also remove the check that all fields are present (since we
@@ -295,9 +294,9 @@ fn assert_zeroable<T: ?::core::marker::Sized>(_: *mut T)
where T: ::pin_init::Zeroable
{}
// Ensure that the struct is indeed `Zeroable`.
- assert_zeroable(#slot);
+ assert_zeroable(slot);
// SAFETY: The type implements `Zeroable` by the check above.
- unsafe { ::core::ptr::write_bytes(#slot, 0, 1) };
+ unsafe { ::core::ptr::write_bytes(slot, 0, 1) };
},
};
let this = match this {
@@ -309,20 +308,19 @@ fn assert_zeroable<T: ?::core::marker::Sized>(_: *mut T)
},
};
// `mixed_site` ensures that the data is not accessible to the user-controlled code.
- let data = Ident::new("__data", Span::mixed_site());
- let init_fields = init_fields(&fields, pinned, &data, &slot);
+ let init_fields = init_fields(&fields, pinned);
let field_check = make_field_check(&fields, init_kind, &path);
Ok(quote_spanned! { Span::mixed_site() => {
// Get the data about fields from the supplied type.
// SAFETY: TODO
- let #data = unsafe {
+ let data = unsafe {
use ::pin_init::__internal::#has_data_trait;
// Can't use `<#path as #has_data_trait>::#get_data`, since the user is able to omit
// generics (which need to be present with that syntax).
#path::#get_data()
};
- // Ensure that `#data` really is of type `#data` and help with type inference:
- let init = #data.__make_closure::<_, #error>(
+ // Ensure that `data` really is of type `data` and help with type inference:
+ let init = data.__make_closure::<_, #error>(
move |slot| {
#zeroable_check
#this
@@ -380,12 +378,7 @@ fn get_init_kind(rest: Option<(Token![..], Expr)>, dcx: &mut DiagCtxt) -> InitKi
}
/// Generate the code that initializes the fields of the struct using the initializers in `field`.
-fn init_fields(
- fields: &Punctuated<InitializerField, Token![,]>,
- pinned: bool,
- data: &Ident,
- slot: &Ident,
-) -> TokenStream {
+fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -> TokenStream {
let mut guards = vec![];
let mut guard_attrs = vec![];
let mut res = TokenStream::new();
@@ -413,16 +406,16 @@ fn init_fields(
let ident = member.as_ident();
let slot = if pinned {
- quote! {
+ quote_spanned! { Span::mixed_site() =>
// SAFETY:
// - `slot` is valid and properly aligned.
// - `make_field_check` checks that `&raw mut (*slot).#member` is properly aligned.
// - `make_field_check` prevents `#member` from being used twice, therefore
// `(*slot).#member` is exclusively accessed and has not been initialized.
- (unsafe { #data.#ident(#slot) })
+ (unsafe { data.#ident(slot) })
}
} else {
- quote! {
+ quote_spanned! { Span::mixed_site() =>
// For `init!()` macro, everything is unpinned.
// SAFETY:
// - `&raw mut (*slot).#member` is valid.
@@ -431,7 +424,7 @@ fn init_fields(
// `(*slot).#member` is exclusively accessed and has not been initialized.
(unsafe {
::pin_init::__internal::Slot::<::pin_init::__internal::Unpinned, _>::new(
- &raw mut (*#slot).#member
+ &raw mut (*slot).#member
)
})
}
--
2.54.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] rust: pin-init: internal: pin_init: provide span for slot projection
2026-09-16 12:11 [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
2026-09-16 12:11 ` [PATCH 1/3] rust: pin-init: internal: pin_init: emit `slot` using mixed site hygiene Gary Guo
2026-09-16 12:11 ` [PATCH 2/3] rust: pin-init: internal: pin_init: use `slot` identifier directly with mixed site Gary Guo
@ 2026-09-16 12:11 ` Gary Guo
2026-09-16 18:41 ` [PATCH 4/3] rust: pin-init: util: use span of `Index` for generated identifiers Gary Guo
2026-09-18 11:53 ` [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
4 siblings, 0 replies; 6+ messages in thread
From: Gary Guo @ 2026-09-16 12:11 UTC (permalink / raw)
To: Benno Lossin, Gary Guo, Miguel Ojeda, Boqun Feng,
Björn Roy Baron, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan
Cc: rust-for-linux, linux-kernel
When initializing a field, pin-init first projects the full slot to a slot
of the field, then initialize it by invoking a method. Currently the span
location is not explicitly set, so the error message points to the full
macro invocation.
Improve it by provide a span, so Rust will point to the specific fields
causing the error when type check fails.
Old error message:
error[E0308]: mismatched types
--> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
|
8 | let _ = init!(Foo { a: () });
| ---------------^^---
| | |
| | expected `usize`, found `()`
| arguments to this method are incorrect
New error message:
error[E0308]: mismatched types
--> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
|
8 | let _ = init!(Foo { a: () });
| ---^^
| | |
| | expected `usize`, found `()`
| arguments to this method are incorrect
Signed-off-by: Gary Guo <gary@garyguo.net>
---
rust/pin-init/internal/src/init.rs | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs
index a77ffef9926b..1d2db93dd33d 100644
--- a/rust/pin-init/internal/src/init.rs
+++ b/rust/pin-init/internal/src/init.rs
@@ -404,9 +404,10 @@ fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -
}
};
let ident = member.as_ident();
+ let span = Span::mixed_site().located_at(ident.span());
let slot = if pinned {
- quote_spanned! { Span::mixed_site() =>
+ quote_spanned! { span =>
// SAFETY:
// - `slot` is valid and properly aligned.
// - `make_field_check` checks that `&raw mut (*slot).#member` is properly aligned.
@@ -415,7 +416,7 @@ fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -
(unsafe { data.#ident(slot) })
}
} else {
- quote_spanned! { Span::mixed_site() =>
+ quote_spanned! { span =>
// For `init!()` macro, everything is unpinned.
// SAFETY:
// - `&raw mut (*slot).#member` is valid.
@@ -432,6 +433,7 @@ fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -
// `mixed_site` ensures that the guard is not accessible to the user-controlled code.
let guard = format_ident!("__{ident}_guard", span = Span::mixed_site());
+ let full_span = kind.span();
let init = match kind {
InitializerKind::Value { value, .. } => {
@@ -440,14 +442,13 @@ fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -
.map(|(_, value)| quote!(#value))
.unwrap_or_else(|| quote!(#member));
- quote! {
+ quote_spanned! { full_span =>
#(#attrs)*
let mut #guard = #slot.write(#value);
-
}
}
InitializerKind::Init { value, .. } => {
- quote! {
+ quote_spanned! { full_span =>
#(#attrs)*
let mut #guard = #slot.init(#value)?;
}
@@ -458,7 +459,7 @@ fn init_fields(fields: &Punctuated<InitializerField, Token![,]>, pinned: bool) -
// A tuple field has no name that could be bound here (the `_0` identifiers are considered
// implementation detail and not user-facing).
let binding = match member {
- Member::Named(ident) => quote! {
+ Member::Named(ident) => quote_spanned! { span =>
#(#cfgs)*
// Allow `non_snake_case` since the same warning is going to be reported for the
// struct field.
--
2.54.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 4/3] rust: pin-init: util: use span of `Index` for generated identifiers
2026-09-16 12:11 [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
` (2 preceding siblings ...)
2026-09-16 12:11 ` [PATCH 3/3] rust: pin-init: internal: pin_init: provide span for slot projection Gary Guo
@ 2026-09-16 18:41 ` Gary Guo
2026-09-18 11:53 ` [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
4 siblings, 0 replies; 6+ messages in thread
From: Gary Guo @ 2026-09-16 18:41 UTC (permalink / raw)
To: Benno Lossin, Gary Guo, Miguel Ojeda, Boqun Feng,
Björn Roy Baron, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan
Cc: rust-for-linux, linux-kernel
Use the span of `Index` for generated identifiers, so diagnostics can point
to the span of the index.
Signed-off-by: Gary Guo <gary@garyguo.net>
---
Follow up to also improve the diagnostics for tuple structs.
---
rust/pin-init/internal/src/util.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/rust/pin-init/internal/src/util.rs b/rust/pin-init/internal/src/util.rs
index ed2c78f0658f..0b5c28b21091 100644
--- a/rust/pin-init/internal/src/util.rs
+++ b/rust/pin-init/internal/src/util.rs
@@ -41,7 +41,7 @@ impl MemberExt for Member {
fn as_ident(&self) -> Ident {
match self {
Member::Named(ident) => ident.clone(),
- Member::Unnamed(Index { index, .. }) => format_ident!("_{index}"),
+ Member::Unnamed(Index { index, span }) => format_ident!("_{index}", span = *span),
}
}
base-commit: 3b3ff9034a497fb3b8429f6fe8ba5697bc7dcebd
prerequisite-patch-id: 84717125cba2ef134e74459d283b3206649b3b03
prerequisite-patch-id: 9f34c2d1fc9699479209cd0c98ec43a70dca8747
prerequisite-patch-id: 830ff446f1ac103336c3b30c9914e9a22c70e577
--
2.54.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 0/3] rust: pin-init: provide better span for diagnostics
2026-09-16 12:11 [PATCH 0/3] rust: pin-init: provide better span for diagnostics Gary Guo
` (3 preceding siblings ...)
2026-09-16 18:41 ` [PATCH 4/3] rust: pin-init: util: use span of `Index` for generated identifiers Gary Guo
@ 2026-09-18 11:53 ` Gary Guo
4 siblings, 0 replies; 6+ messages in thread
From: Gary Guo @ 2026-09-18 11:53 UTC (permalink / raw)
To: Gary Guo, Benno Lossin, Miguel Ojeda, Boqun Feng,
Björn Roy Baron, Andreas Hindborg, Alice Ryhl, Trevor Gross,
Danilo Krummrich, Daniel Almeida, Tamir Duberstein,
Alexandre Courbot, Onur Özkan
Cc: rust-for-linux, linux-kernel
On Wed Sep 16, 2026 at 1:11 PM BST, Gary Guo wrote:
> When initializing a field, pin-init first projects the full slot to a slot
> of the field, then initialize it by invoking a method. Currently the span
> location is not explicitly set, so the error message points to the full
> macro invocation.
>
> Improve it by provide a span, so Rust will point to the specific fields
> causing the error when type check fails.
>
> Old error message:
>
> error[E0308]: mismatched types
> --> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
> |
> 8 | let _ = init!(Foo { a: () });
> | ---------------^^---
> | | |
> | | expected `usize`, found `()`
> | arguments to this method are incorrect
>
> New error message:
>
> error[E0308]: mismatched types
> --> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
> |
> 8 | let _ = init!(Foo { a: () });
> | ---^^
> | | |
> | | expected `usize`, found `()`
> | arguments to this method are incorrect
>
> ---
> Gary Guo (4):
> rust: pin-init: internal: init: emit `slot` using mixed site hygiene
> rust: pin-init: internal: init: use `slot` identifier directly with mixed site
> rust: pin-init: internal: init: provide span for slot projection
> rust: pin-init: internal: use span of Index for generated identifiers
Applied to pin-init-next.
Best,
Gary
^ permalink raw reply [flat|nested] 6+ messages in thread